Title :
A novel optical accelerometer
Author :
Abbaspour-Sani, Ebrahim ; Huang, Ruey-Shing ; Yee kwok, Chee
Author_Institution :
Dept. of Electron., New South Wales Univ., Sydney, NSW, Australia
fDate :
5/1/1995 12:00:00 AM
Abstract :
A novel accelerometer based on a PIN photo-detector and a micro-machined cantilever-beam-supported optical shutter with seismic mass has been designed, fabricated, and tested. Anisotropic wet etching of <110> orientation silicon in KOH is used to fabricate an optical shutter consisting of evenly spaced vertically etched slots. The shutter, which also constitutes the seismic mass of the accelerometer, is suspended by two cantilever beams. The special structure of the device and the high aspect ratio of the cantilever beams (7.5) permit freedom of the movement for the proof mass (the shutter) on the /spl plusmn/X axis only. The actual size of the device is 3/spl times/4 mm and its amplified output varies linearly from -3.6 V to +3.6 V for accelerations from -84 g to +84 g. The measured resonant frequency of the device is 3.2 KHz. A dual diode structure is chosen for the photo-detector to compensate for temperature drift and the amplified output voltage changes by less than 40 mV for a temperature variation from 25/spl deg/C to 50/spl deg/C.<>
Keywords :
acceleration measurement; accelerometers; micromechanical devices; p-i-n photodiodes; photodetectors; -3.6 to 3.6 V; 25 to 50 degC; 3.2 kHz; PIN photo-detector; Si; amplified output; aspect ratio; dual diode structure; evenly spaced vertically etched slots; micro-machined cantilever-beam-supported optical shutter; optical accelerometer; resonant frequency; seismic mass; temperature drift; Acceleration; Accelerometers; Anisotropic magnetoresistance; Geometrical optics; Optical design; Silicon; Structural beams; Temperature; Testing; Wet etching;
Journal_Title :
Electron Device Letters, IEEE
